Island



(No Model.)

M. L. BOSWORTH. DENTAL MALLET.

No. 548,602. Patented OGL. 22', 1895.

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UNITED STATES PATENT rrncn.

MARTIN L. BOSWORTH, OF WARREN, RHODE ISLAND.

DENTAL MALLET.

SPECIFICATION forming part of Letters :Patent No. 548,602, dated October 22, .1895.

Application filed May 19,1894. Serial No. 511,743- (No model.)

To all whom, t may concern:

Be it known that 1, MARTIN L. BosWoRTH, of the town of Warremin the county of Bristol, in the State of Rhode Island,have invented a certain new and useful Improvement in Dental Mallets; and I declare the following to he a specification thereof, reference being had to the accompanying drawings.

Like letters indicate like parts.

Figure lis a side elevation of my invention with the parts in their normal position. Fig. 2 is the same with the parts in the position when the blow is delivered on the plunger.

My invention is a dental instrument for compacting gold in filling teeth; and it consists of 'the novel construction and combination of the elements hereinafter particularly described, and specifically set forth in the claims.

In the drawings, A is a handle, having a longitudinal tubular bore, which, near its outer extremity, is enlarged to form a tubular chamber continuous with said bore.

B is a box-like extension of the handle which forms a case for the inclosed actuating mechanism. This case has its sides, ends, and bottom integral, and it is covered by a plate (not shown) which is fastened in place by screws passing into the screw-holes a. in the case or extension. The inner end of the eX- tensiou or case B has through it a tubular opening continuous with the bore of the handie A.

C is the plunger or rod which is freely movable longitudinally in the tubular bore of the handle A and case B. At its outer end this plunger has a head or socket piece D, in whose screw-threaded bore the plugger or tool E is secured.

Near the inner end of the plunger C is the head-block F, having a screw-threaded bore, by which it is adj ustably fitted upon said plunger by the screw-threads of the latter. The head-block F is held in position upon the plunger by the set-screwb. The headblock F has a transverse slot and groove in which is mounted a paWl G, Whose eylindricallyshaped inner end is mounted loosely in said slot and groove of the head-block F, and which has a slight oscillation therein. A spring e,

fastened to the pawl G by a screw d, has its free end bearing against a shoulder e made in the head-block F.

A hammer H, Whichis somewhat triangular in form, is pivotally mounted in the case B upon the screwf. This hammer has the projecting portions g and h, the shoulder m, and the slot fn. The free end of the pawl G nor mally abuts the said shoulder m.

I is a spring mounted by a cylindricallyshaped extension o in a groove pin the case B. Its free end bears against the projection i of the hammer H. A short rigid arm extends from the spring I near its mounted end at a right angle and has a hole or opening through which the screw-bolt J passes. This bolt also passes through a hole in the outer end of the case B and by means of a screwthread engages with the nut or knob K.

A spiral spring p surrounds the plunger or rod C near its outer end and has its bearings on the inner end of the socket-piece D and on the inner end of the chamber in the han dle' A. There is a stop-block on the inner surface of the case, as shown at fr.

The normal position of the parts is illustrated in Fig. l. The expansion of the spiral spring p keeps the plugger E extended. The free end of the paWl abuts the shoulder m of the head-block F. Vhen the implement is in use, the plugger-point is pressed with sufcient force upon the gold lling by the hand of the operator grasping the handle A. This movement carries the plunger C inwardly until the head-block F attached thereto strikes against the stop-block r, which limits such in- Ward movement of the plunger. This movement of the head-block F causes the end of the pawl Gr to press the hammer Il, so that it turns on its pivot fand by its projection h bends the spring I. This movement of the hammer H continues until the end of the pawl Gr slips off from the shoulder m of said hammer, which tripping motion is facilitated by the projection g of the hammer coming in contact with the edge of said paWl and foreing it from its frictional engagement with said shoulder. As soon as the pawl is thus tripped, its end is brought into line with the slot n of the hammer H. The spring I is now free to act and causes the hammer H to deliver a blow upon the end of the plunger C. In Fig.

IOO

2 the position of the parts at this juncture is seen. The pawl G has entered the slot n of the hammer and the spring c of the paWl is compressed against the shoulder eot the headblock F.

As soon as the pressure by the operator is relieved, the spring p carries the plunger outwardly again, and the head-block F, traveling with the plunger, returns to its former position, thus clearing the pawl Gfrom the slot n of the hammer. The spring c then throws the pawl outwardly, so that its end again abuts and engages the shoulder @of the hammer.

By means of the bolt J and the nut K the tension of the spring I can be adjusted, and the force of the blow of the hammer is thus regulated.

I claim as a novel and useful invention and desire to secure by Letters Patent- 1. In a device of the class described7 the combination with the hammer of a pivoted spring adapted to exert pressure at one side of its pivot, said spring having an angular extension from its pivotal point, and a tension device adapted to exert pressure on said angular extension to vary the effective pressure of the spring upon the hammer.

2. A device of the class described comprising a casing having a plunger therein protruding therefrom, a block on the plunger adjacent its inner end, a spring supported rod pivoted to the block, a pivoted hammer having a shoulder to receive pressure of the rod, a cam adjacent the shoulder to move the rod from the latter, a recess also adjacent the shoulder' to receive the end of the-rod when moved from the shoulder, an angular spring pivoted at its apex and having one extremity in engagement with the hammer, and a tension device passed through the end of the casing and connected with the other end ot' the spring to vary the pressure of the spring upon the hammer.

3. A device of the class described,comprising a casing having a plunger movable therein, a hammer adapted to operate said plunger, a pivoted spring arranged to exert pressure upon the hammer and means for moving the spring on its pivot to vary its effective pressure.

4. A device of the class described, comprising a casing having a plunger arranged to move therein, an adjustable block on the plunger, a hammer adapted to operate the plunger, connections between the said block and the hammer to retract the latter, a pivoted spring having connection with the hammer at one side of its pivot, and means for moving the spring on its pivot to vary its pressure upon the hammer.

MARTIN L. BOSl/VORTH. lVitnesses:

WARREN R. PERCE, DANIEL W. PINK. 

